package etl.dispatch.util;

public class HexStringUtil {
	/**
	 * 字节数组转成16进制表示格式的字符串
	 *
	 * @param byteArray
	 *			需要转换的字节数组
	 * @return 16进制表示格式的字符串
	 **/
	public static String toHexString(byte[] byteArray) {
		if (byteArray == null || byteArray.length < 1)
			throw new IllegalArgumentException("this byteArray must not be null or empty");
 
		final StringBuilder hexString = new StringBuilder();
		for (int i = 0; i < byteArray.length; i++) {
			if ((byteArray[i] & 0xff) < 0x10)//0~F前面不零
				hexString.append("0");
			hexString.append(Integer.toHexString(0xFF & byteArray[i]));
		}
		return hexString.toString().toLowerCase();
	}


	/**
	 * 16进制的字符串表示转成字节数组
	 *
	 * @param hexString
	 *			16进制格式的字符串
	 * @return 转换后的字节数组
	 **/
	public static byte[] toByteArray(String hexString) {
		if (hexString == null || hexString.isEmpty())
			throw new IllegalArgumentException("this hexString must not be empty");
 
		hexString = hexString.toLowerCase();
		final byte[] byteArray = new byte[hexString.length() / 2];
		int k = 0;
		for (int i = 0; i < byteArray.length; i++) {
						//因为是16进制，最多只会占用4位，转换成字节需要两个16进制的字符，高位在先
			byte high = (byte) (Character.digit(hexString.charAt(k), 16) & 0xff);
			byte low = (byte) (Character.digit(hexString.charAt(k + 1), 16) & 0xff);
			byteArray[i] = (byte) (high << 4 | low);
			k += 2;
		}
		return byteArray;
	}
}
